uremia

uremia, condition resulting from advanced stages of kidney failure in which urea and other nitrogen-containing wastes are found in the blood. Uremia can be caused by NSAIDs (nonsteroid anti-inflammatory drugs), especially in older patients treated primarily with ibuprofen for arthritis. Some of the early signs of uremia are lethargy, mental depression, loss of appetite, and edema; later symptoms include diarrhea, anemia, convulsions, coma, and a gray-brown coloration. Treatment of uremia, which is directed at the underlying kidney disease, is usually with dialysis and renal transplantation. Treatments with genetically engineered erythropoietin decrease the complication of anemia. See nephritis; nephrosis.

Excess nitrogenous waste products in the blood and their toxic effects. Kidney impairment (see Bright disease; diabetes mellitus; hypertension; kidney failure; nephritis) or disorders that hinder urine excretion (e.g., prostatic disorders) allow urea and other protein waste products to accumulate. Symptoms usually start with fatigue and loss of concentration. They may include itching and muscle twitches; dry, flaky, yellowish skin; dry mouth, metallic taste, and ammonia breath; and nausea, vomiting, diarrhea, and constipation. Advanced stages affect the nervous, cardiovascular, and respiratory systems and can lead to hypertension, seizures, heart failure, and death. If the underlying disorder cannot be treated, dialysis or kidney transplant may be required.

Learn more about uremia with a free trial on Britannica.com.

Uremia is a term used to loosely describe the illness accompanying kidney failure (also called renal failure). In kidney failure, urea and other waste products, which are normally excreted into the urine, are retained in the blood. Early symptoms include anorexia and lethargy, and late symptoms can include decreased mental acuity and coma. It is usually diagnosed in kidney dialysis patients when the glomerular filtration rate, a measure of kidney function, is below 50% of normal.

Azotemia is another word that refers to high levels of urea, but is used primarily when the abnormality can be measured chemically but is not yet so severe as to produce symptoms. Uremia can also result in fibrinous pericarditis. There are many dysfunctions caused by uremia affecting many systems of the body, such as blood (lower levels of erythropoietin), sex (lower levels of testosterone/estrogen) and bones (osteoporosis and metastatic calcifications).

Causes

Besides renal failure, the level of urea in the blood can also be increased by:

• increased production of urea in the liver, due to:
• high protein diet
• increased protein breakdown (surgery, infection, trauma, cancer)
• gastrointestinal bleeding
• drugs (e.g. tetracyclines and corticosteroids)

• decreased elimination of urea, due to:
• decreased blood flow through kidney (e.g. hypotension, cardiac failure)
• urinary outflow obstruction

• dehydration
• kidney failure
• chronic infection of the kidney, such as chronic pyelonephritis

References